Part type creation

In journal Entry Account, I want to set new part type, ‘Subcontractor’ (in addition to / instead of Supplier and Customer) and must show subcontractor_names in ‘Party’ Field. Now it shows only ‘Customer’ and ‘Supplier’. How can I include ‘Subcontractor’ docType also to the Party Type.

I searched here and there but I didn’t get right solution. I read it as hard coded. I am not sure about this.

Can anybody know to get rid of this problem?

@Amalendu this is a bigger change. Why not classify Subcontractor under Supplier (?)